Do Morning-After Pills Work in Overweight Women? European Regulators Investigate

European regulators are investigating whether the “morning-after pill” is effective in women who are overweight or obese. According to CBS, the European Medicines Agency said in a statement on Friday that it is reviewing a number of emergency contraceptives containing levonorgestrel as the active ingredient. The contraceptives being reviewed include Levodonna, Levonelle/Postinor and Norlevo, which has the same formula as Plan B One-Step. ellaOne, which contains ulipristal acetate as its main active ingredient, is also going to be reviewed.

The investigation follows a November 2013 report indicating that some morning-after pills may not work effectively for women who are overweight. HRA Pharma, the French manufacturer of Norlevo, had said that the label on Norlevo was being changed to indicate that it is not effective in women who weigh more than 176 pounds. Specifically, the pill starts to lose its efficacy in women over 165 pounds and is not advised for women over that weight, the warning said. Based on independent testing, HRA Pharma found that increasing the amount of levonorgestrel did not increase the effectiveness for women in that weight range. The company advised these women to speak to their doctors about other forms of contraception.

Previous research has shown that the morning-after pill tends to not work as well in overweight women. In 2011, Contraception published a study showing that emergency contraceptives were three times as likely to not work in obese women compared to normal-weight women. The risk of pregnancy was higher for pills that contain levonorgestrel than for those that have ulipristal acetate.

Morning-after pills are a group of medications that are used to prevent an unwanted pregnancy if the main form of contraception fails or in the event of unprotected sex. Plan B One-Step, Plan B and ella are three types of morning –after pills approved for sale in the United States. Plan B One-Step, which contains 1.5 mg dose of levonorgestrel, is available over the counter for women of all ages. Plan B can be bought over the counter for any woman over the age of 17, and Ella is only available by prescription.